A Guide to Shadow Bending

Chapter 8

The Yin & Yang islands:

The question may have formed in your mind. You may have tried to answer it yourself, forgot about it, or just don't care. Or maybe you've waited for me to upload a new chapter to tell you guys the answer. Well, here it is

Q: Why didn't anyone travel to the Yin & Yang islands to check and make sure the benders there were dead?

A: Because the island is impossible to reach. Surrounding the Yin Yang island are a series of obstacles only the benders of Shadow and Light can pass. 

All around the Light Kingdom there are several tide pools and whirlpools. There are also some jagged rocks that could easily break a hole in your ship and sink it, as well as the sea monsters that live nearby. As if that's not enough, the sun hits a shield above the water and tricks the light making it seem like something that isn't there is, or something that is there isn't. Only a Light Bender can pass through these obstacles successfully. 

The bender simply uses their element to create a Light Bridge or other materials they'd need to get through. 

Why can't an Air Bender simply fly over the obstacles or create an air pocket and walk underwater?

As for underwater, the sea monsters take their job seriously. As for flying,  a thick fog looms above Lightside and they wouldn't be able to see the island if they went too high, and if they went too low they'd be poisoned by the fumes of the Lightlock plant that grows all around the beaches of Lightside. (Note: Light Benders are the only ones immune to this plants poison). 

As for Shadowside, a thick fog rests just above the water, clouding all view. This fog starts out normal, then turns black as night. You wouldn't know which way to go to even turn around! Along with the fog are many thousands of sharp spear-like rocks that jut up from the water like knives, these rocks crash into the boats and break them in half. 

Above Shadowside is a layer of heavy mist. This mist is actually acid floating above the Shadow Nation. It can burn a person to death the farther they get into the mist. 

Whales also lurk around the darkness of Shadowside, these whales are part shark and have an unquenchable thirst for human blood. 

Again, only Shadow Benders can bend the fog away and build Shadow Bridges above or around the rocks. 

Why can't a Water Bender just bend the water up to get over the rocks?

1. The fog is too heavy. 

2. This fog releases a gas that is in a way like chi blocking, it prevents water benders from doing this. Many evil men have tried to recreate this fog to use against their enemies, but the ShadowPhantom has thus far prevented that from happening. 

All these things have been sent as warnings to the other four nations, if anyone dared enter the realm of shadows, or the light labyrinth, they did so knowing that their lives were doomed without the aid of a Shadow or Light Bender. 

On another note, 

After the war it was made illegal for anyone on the island to leave or have any communication with the outside world.